Making a Digital Negative for Bromoil Contact Printing
Firstly what follows is all based on Dan Burkholders “Making Digital Negatives for Contact Printing”. Dans book is magnificent and goes into superb detail, but for my purposes I only need a small portion of the information he gives. I have therefore cut through the minutiae I don’t need, (interesting though it is). I have also made a few tweaks to suit my Bromoils. The basic process is:

1) The starting point for the purpose of these notes is: a positive mono picture on the computer.
2) In Photoshop I apply: Image-Adjustments-Curves. An appropriate curve is applied.
3) Then apply: Image-Adjustments-Invert.
4) Then apply: Image-Mode-RBG
5) Then set the colour on your tool pallet.
6) Then apply: Edit-Fill and the fill box appears. In the “Contents Use” section, apply Foreground Colour. In the “Blending Mode” section, apply: Colour. In the “Opacity” box set to 100%. Click OK and the image then colourizes.
7) Print on to acetate as you would a normal print. DO NOT set the printer to “Ink Jet Transparency”. This defaults at 360 dpi and the result comes out like a ploughed field. I set my printer to “Photo Quality Ink Jet Paper” which defaults at 1440dpi. (I estimate Dan Burkholder saved me the cost of his book with this information).
8) I leave the completed negative to dry overnight, “sticky side” up, in a dust free area. I then store it with a piece of ordinary A4 paper sitting on the “sticky side”. DO NOT store it directly in a plastic sleeve without the said paper. It will stick and lumps of image will pull off.

That was a précis of the main steps. Now the few tweaks I mentioned:
Item 2 Curves: I found the “silvergf” curve supplied by DB to be the nearest for Bromoils. I did however change it slightly to try and veil the highlights.

Note 5 Fill Colour: Before I got hold of BDs book, I tried black ink negs. I found that they were very “blocky”, and either burned out or blocked up.
DB recommends red negs of: C=0%; M=71% and Y=71%. I found that these were also “blocky” and not easy to print. I therefore tried different mixes and found that C=0%; M=100%; Y=100% suited my set-up best. It may well be that differing enlarger lamps at differing colour temperatures have some affect on the exposure through these negs. The attachments show the colour differential of the two negs.

Note 7 Transparency material: I have found two types of ink jet transparency material. One has a very defined texture, which can be felt and seen. This I purchased from a company called Perma Jet. It was the material on which I carried out all my tests. When I bought my next box, low and behold I found they had totally changed the material. On this new batch’ it was impossible to tell which side was which. There was a slice off one corner, which was placed top right in the printer to ensure correct the orientation. Perma Jet were not my favorite people at this time, I did however find that 3Ms produced the textured acetate at a fifth of the cost of Perma Jet. I therefore use the 3M material. I’m not suggesting that it is superior to the untextured acetate, simply that I didn’t want to start testing all over again. An advantage of the untextured material is that it doesn’t have the “sticky” problem to the same degree as the textured.

Contact print and bromoil in the normal way.